Membrane and Desalination Technologies (original) (raw)
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Membrane desalination technologies in water treatment: A review
Water Practice and Technology
One of the most pressing problems worldwide is inadequate access to potable water. Many technologies have been applied to address this through research to find robust but inexpensive methods of desalination that offer high fluxes and use less energy, while reducing chemical use and environmental impact. Membrane desalination technology is universally considered to solve water shortage problems due to its high efficiency and lower energy consumption than distillation methods. This review focuses on the desalination performance of membrane technologies with consideration of the effect of driving force, potential technologies, membrane types, flux, energy consumption and operating temperature, etc. Pressure driven membrane processes (MF, UF, NF, RO), and their fouling propensity and major drawbacks are discussed briefly. Membrane characteristics and the effects of operating conditions on desalination are also covered. Organic-hybrid and inorganic membrane materials can offer advantages...
Membrane developed systems for water and wastewater treatment
Environmental Progress, 2005
Existing water supplies may be limited in quantity or quality for meeting the increasing demands from population growth and industry expansion. In many arid and semiarid areas, providing the large volume of water required for industrial, agricultural, recreational, and potable applications is especially difficult. So, searching for "new" water sources is a task for researchers in the water works field. Municipal wastewater, which constitutes between 75 and 80% of consumed water in most cities, is one of the most reliable sources of water because its volume varies little throughout the year [1]. Through suitable treatment, reclaimed wastewater can meet various water quality requirements for potential wastewater reuse [2]. A wide variety of treatment technologies have been studied and developed for reclaiming secondary effluents, such as processes coupling, chemical oxidation, depth filtration, adsorption, air stripping, ion exchange, electrodialysis, surface filtration, chemical precipitation, and membrane processes [3]. Membrane treatment has increased in prevalence during recent years because it represents an alternative treatment that produces stable high water quality for compliance with stringent water quality regulations. Many studies have been performed concerning the treatment of secondary effluent with membrane processes. Ghayeni et al. [1] applied four different low operating pressure reverse-osmosis (RO) membranes [PVD and CTA from Hydranautics (San Diego, CA), TFCL from Koch membrane (San Diego, CA), and NF45 from FilmTech (Toronto, Ontario, Canada)], with MF pretreatment, to evaluate the high-quality production from secondary effluent. Results showed that the TFCL membrane was the most suitable membrane for treatment of secondary effluents because of its better rejection ability: a 99.2% rejection of conductivity, 100%
Membrane-based seawater desalination: Present and future prospects
Desalination, 2017
Given increasing regional water scarcity and that almost half of the world's population lives within 100 km of an ocean, seawater represents a virtually infinite water resource. However, its exploitation is presently limited by the significant specific energy consumption (kWh/m 3) required by conventional desalination technologies, further exasperated by high unit costs ($/m 3) and environmental impacts including GHG emissions (g CO2-eq/m 3), organism impingement/entrainment through intakes, and brine disposal through outfalls. This paper explores the state-of-the-art in present seawater desalination practice, emphasizing membrane-based technologies, while identifying future opportunities in step improvements to conventional technologies and development of emerging, potentially disruptive, technologies through advances in material science, process engineering, and system integration. In this paper, seawater reverse osmosis (RO) serves as the baseline conventional technology. The discussion extends beyond desalting processes into membrane-based salinity gradient energy production processes, which can provide an energy offset to desalination process energy requirements. The future membrane landscape in membrane-based desalination and salinity gradient energy is projected to include ultrahigh permeability RO membranes, renewable-energy driven desalination, and emerging processes including closed-circuit RO, membrane distillation, forward osmosis, pressure retarded osmosis, and reverse electrodialysis according various niche applications and/or hybrids, operating separately or in conjunction with RO.
Introductory Chapter: An Overview of Recent Advances in Membrane Technologies
Advances in Membrane Technologies, 2020
Environmental changes, global warming, and inappropriate planning are two sides of the worldwide water shortage coin [1-3]. Figure 1 shows the status of different countries based on water-stressed scenario [4]. Based on United Nations report, more than 2 billion people will experience water scarcity by 2050 [4]. All the previous projections show the vitality of drinking water production and desalination technologies. Currently, there exist two main commercial water-treatment process classes including thermal-based processes (including multistage flash distillation (MSF), vapor compression (VC), and multieffect distillation (MED)) and membrane filtration processes (including reverse osmosis (RO), nanofiltration (NF), and related energy recovery devices (ERD)). Thermal processes were more common previously. However, membrane technologies are outweighing the older processes. Main reasons for RO desalination process growth have mentioned to be rapid technical advances along with its simplicity and elegance [5-9]. Despite all advances in the field, fouling in its different types (colloidal matters, organic fouling of natural and synthetic chemicals, inorganic fouling (scaling), and biological fouling (biofouling)) is the remaining issue of industrial membrane processes [9, 10]. Various types of fouling will result in feed pressure increment and higher operational costs, more frequent requirement of chemical cleaning of the modules and shortened lifetime of the membranes. Fouling types happen simultaneously and could affect each other. This is while biofouling is identified as the critical issue as it is imposed to the membrane surface by living and dynamic microbiological cells and viruses. As the biological attachment, division of the cells and colonization on the surface occurs, the microbiological species and the exopolymeric substance produced by them, create resistance to antimicrobial treatments and the resulted biofouling starts to impose bio-corrosion and lowering the performance of the system [11]. Exposure of the membrane systems to feed's biological contamination highly depends on the environmental factors of the feed itself (nutrient content, available biological species, temperature, light, turbidity, and currents (tides and waves)) [12]. Items under feed water and microorganism classes are related to the microorganism proliferation and conditions supporting their existence. This is while main efforts over process enhancement and modification of membranes are attributed to the membrane-specific properties such as composition and surface structure-characteristics (classified under the title of membrane properties). Apparently, the issue of biofouling could own various levels of severity in different locations. Biofouling is mentioned to be responsible for 45% of the overall fouling that occurred in nanofiltration (NF) and RO plants [13-16].
Recent trends in membranes and membrane processes for desalination
Desalination, 2016
Access to clean water resource continues to be the most urgent and pressing global issue where hiking economic and ecological needs have urged for more water-efficient technologies. Membrane-based separations for desalination are playing an increasingly important role to provide adequate water resources of desirable quality for a wide spectrum of designated applications. The engagement of multidisciplinary research areas into the commercial membrane and membrane systems offers an opportunity to refine and optimise current techniques as well as provides new insight and novel methods of purifying water. The advancement of material science and engineering reveals the potentials to solve real-world practical problems and heighten the current technologies. This review highlights some of the latest notable achievements of novel advanced membrane materials and emerging membrane processes for water solution. The unique characteristics of advanced membranes and emerging membrane processes in leading the state-of-the-art desalination are presented. Lastly, the future directions for research, development and commercialization of membrane and membrane processes are critically discussed. It is expected that, the promising and well-adapted characteristics possessed by the novel membranes and advanced membrane processes can provide meaningful inspiration for breakthrough technologies and solutions where soon they will be translated into exploitable innovations in industries.
Reverse Osmosis Membranes for Desalination of Brackish Water
University of Waterloo, 2020
Reverse osmosis (RO), which is commonly used for different water purification and desalination applications, is a remarkable process to separate dissolved inorganic and organic compounds from water. Over traditional methods of water treatment and purification, RO has many benefits such as production of high quality drinking water, simultaneous elimination of multiple pollutants, and simple operation procedure. As drinking water supplies are declining and demand for high quality water is increasing worldwide, RO membrane based water treatments will most probably continue to develop. This research was aimed at better understanding the behavior of the thin film composite (TFC) polyamide membrane used in RO process under various operating conditions. The performance of RO membrane was evaluated in terms of salt rejection and water flux to simulate brackish water desalination process. The operating conditions included salt concentrations ranging from 2000 to 6000 ppm and operating pressure ranging from 100 to 250 psi. Based on experimental results, the performance of the TFC polyamide RO membrane was estimated at higher operating pressures (300-1000 psi). Based on mass transfer coefficient , solute transport parameter and water permeability that is characteristic of the membrane. In addition, the potential of using the TFC RO membrane to process water during oil and gas productions (with 1.5-2.5 % salt by weight), was demonstrated in this study. Besides simulation, experiments were conducted using real water as the feed solution. Dedication This is dedicated to the one I love. v Table of Contents List of Figures viii List of Tables x List of Tables 2.1 Classification of pressure driven membrane separation processes[9].. .. . .
Maku, 2019
Water scarcity is a long standing issue in many parts of the world. Climate change, population growth, urbanization and anthropogenic activities have led to inadequate water resources availability to meet the demands. Countries like China, India, Middle East and Africa regions have experienced increasing pressure on fresh water resources 1, 2). Desalination and wastewater treatment are pragmatic approaches to augment fresh water supplies in these water stress regions. Conventional and new technologies have been explored to desalinate seawater or brackish water as well as to reclaim wastewater for various purposes. On the other hand, the discharge of wastewater from various industries has resulted in severe pollution. Depending on the sources, the wastewaters may contain organic compounds and inorganic compounds such as dyes, oils and grease, nutrients, pesticides and heavy metal ions. Compound of emerging concerns(CECs), particularly those associated with endocrine disrupting compounds (EDCs), is a new class of pollutants that have raised public concerns due to their harmful effects on human and other organisms even at extremely low concentration 3). As wastewater treatment plant has been identified as a main route for the discharge of CECs into the water bodies, there is a pressing need to efficiently treat the industrial effluents to protect human and aquatic life from intoxication. Furthermore, industrial wastewater reclamation has also been acknowledged as a sustainable option to address the water shortage issues. Membrane technology is a promising technology that plays important roles in achieving the goals.
Membrane technologies for water treatment and agroindustrial sectors
Comptes Rendus Chimie, 2009
Although water is essential for human survival and progress, it is distributed very unevenly and with a different purity over the surface of the earth. A variety of contaminants can be present in raw water, depending on its origin. The size of these contaminants ranges from the micrometer (e.g. bacteria) to the tenths of a nanometer order (ions). Membrane processes like microfiltration, ultrafiltration, nanofiltration and reverse osmosis could be a solution for an advanced physical treatment of water for drinking purposes as well as for agroindustrial sectors. Many applications are well assessed and are expanding very quickly; however, to obtain an ever-growing performance, it is necessary to prepare membranes with tailored structure and transport properties. Characterisation methods play also a role of paramount importance for the selection of the more appropriate membrane for the above-mentioned applications. In this work the main membrane preparation techniques and characterisation methods will be reviewed and discussed. To cite this article: A.
Euromembrane 2000 highlights membrane-based water treatment technologies
Membrane Technology, 2001
The first instalment of our Euromembrane 2000 round-up, which was published i At Euromembrane 2000, Marianne Nystrom in the January 2001 issue of Membrane Technology, looked at developments in i of the Department of Chemical Technology, liquid membranes and ~stillation. The conference aIso looked in detail at water. Lappeenranta University of Technology in treatment, and this article, the second in a series of three summaries covering the j Finland, highlighted some of the potential uses of NE and the advantages which this technology event that was held in Israel during September last year, considers the role which i oEers_ These are different types of membranes are now playing in this area. . Compared with RO, the concentration of a product which cannot pass through a NF membrane costs less because of the Lower pressures which are needed. Examples of this include applications in the pulp and paper industry. NF can be used as a pretreatment method in the production of drinking water. Because part of the salt is retained and parr is permeated, the pressures can be kept lower, and the fluxes higher, than is possible with RO. It also preferentially retains multivalent ions (hardness). If needed, the final step can then use RO, which eliminates the remaining monovalent salts.